Alternating-current dynamo-electric machine.



G. WINTER & F. EIOHBERGr ALTBRNATING GURRENT' DYNAMO ELECTRIC MACHINE."

APPLICATION FILED AUG. 3, 1906.

1,016,865, Patented Feb. 6, 1912.

Fig. I Fig. 2. y is! Inventors Qabr iel Winter, Frledrlch Eichberg,

UNITED STATES. PATENT. OFFICE.

GABRIEL WIN' 'ER, or VIENNA, AUSTRIA-HUNGARY, Am) FRIEDRICH EIcIIEE'E-e, 0E BERLIN, GERMANY, AssIGNoEs TO GENERAL ELECTRIC COMPANY, a COBPQRATION OF NEW YORK.

ALTERNATING-CURRENT DYNAlVlO-ELECTRIG MACHINE.-

1,016,865. Original application filed June 11, 1902,

To all whom it mag concern:

Beit known that we, GABRIEL WINTER and FRIEDRICH EIOHBERG, subjects of the Emperor of Austria-Hungary, residing, respectively, at Vienna, in the Empire of Austria- Hungary, and at Berlin, in the Empire of Germany, have invented certain new and voltages of relatively varying magnitudes, I and means for magnetizing the motor in a second direction at an angle to the first. As described in that application, the means for producing the second magnetization of the motorcomprises a magnetizing winding on either statorv or rotor, which may be separate from the other two windings, or combined with either primary or secondary winding. WVhen a magnetizing winding is placed upon the rotor, :either as an independent winding or. in combination with the secondary winding, current is supplied to it through a second system of brushes displaced ninety electrical degrees from the otherbrushes.

Ourpresent application relates specifically to this modification, in which the magnetizing current is supplied through commutator brushes.

'Qur invention will best be understood by reference to theaccompanying drawings, in whichnetizing winding distinct from the secondary winding of the rotor; Fig. 2 shows themagnetizing combined with the sec- "ondary' winding; Fig, 3 shows an arrange- Specification of Letters Patent.

Figure 1 shows a motor arranged in ac cordancewrth our inventlon, with the mag-' Patented Feb; 6, 1912.

Serial No. 111,180.... Divided and this application filed August 3, 1906. Serial No. 329,022.

electromotive force; Fig. 4: shows a similar arrangement with the secondary winding directly short-circuited; and Fig. 5 shows one suitable arrangement of connections for the magnetizing Winding.

If voltages of the same phase are impressed on the primary and secondary windings (hereinafter referred to as P and s, respectively) of an alternating current transformer, then, when the ratio of these voltages corresponds to the rat-i0 of transformation of P and S, the current flowing in each of the windings will produce one-half of the magnetic field of the transformer,"i. 6., when the ratio of transformation is one, each winding takes one-half the magnetizing current, I or, generally stated, each winding gives one half the total magnetizing ampere turnsewhile the electromotive forces M. F.s) in'duced thereby in the windings will bear to each other a ratio corresponding to theratio of transformation and will be opposed to the respective impressed. voltages; but when the windings P and S are connected to voltages of a ratio different from the ratio of transformation, the winding P will take fromfthe source alarger current, for example, while S will then return current'to the source, since in this example the voltage induced in P is less than the voltage impressed thereon, and since the voltageinduced in "S is greater than the voltage impressed thereon. -The difference between the energies corresponding to these two currents is the total energy loss of the transformer, including ohmic and iron losses. 7

:WVe take advantage of the above transformer action" in one of our arrangements for motor control asffollows: Let the primary and secondary winding system be arranged in the manner illustrated in Fig. 1

of the accompanying diagrammatic drawing, i. e.,'as separate bipolar ring windings disposed in such a way that Scan move independently of- P, while the points of connection to the source and therefore the magnetic poles of S are maintained-on the line w m, (constituting the Working axis) which winding S with a segmental commutator and causing the current to be supplied through brushes situated on line a;- z'za If can be easily attained by providing the supplied to the winding M corresponds as rotor by the primary field on the axis m m,

nearly as possible in phase to the currents in P and S; then a torque is produced which is proportional to the field of winding M, to the ampere turns of the rotor S and to the cosine of the displacement of phase between both of these last magnitudes. The counter electromotive force occurring at the commutator upon the rotation .of the rotor, in the field having. the axis y y, has itsgreatest efiective value on the .line w m, and is in phase with the'magnetic field having the axisy y.

If the phase angle between the electromotive force connected to S (this electromotive force being hereinafter referred to as E and the magnetic field of M is very small and, the influence of the magnetic leakage and ohmic loss is disregarded, then the counter electromotive force due to the rotation which is in phase with the magnetic field of M, is consequently nearly in the same or opposite direction to that of the electro- .motive force connected to the rotor and is also nearly in the same or opposite direction to the electromotive force generated in the since this latter electromotive force is substantially in phase with the electromotive force E impressed on the secondary. With increasing speed the counter electromotive force due to rotation increases, and consequently the resultant electromotive force upon winding S decreases when the counterelectromotive force is opposed to the electromotive force connected to the rotor. v

Any desired speed within practicable limits can be provided for by supplying to said windings voltages of relatively varying magnitudes, that is, by making variations in the difference between the potential (hereinafter called E supplied to the stator winding P, and the potential E supplied to the rotor winding S., If the fall or loss in" potential 'in the windings were not taken into account and the number of turns of windings P and S are assumed equal, then it could be said that the speed which the rotor acquires is proportional to the difference E -E when the magnetic field havmg its axis on the line y y is of constant .strength. That is, when E =E the motor stands-still. If E is greater than E the motor speeds up until the counter-electromotive force, due to rotation, equals E E If E =O, the motor speeds up until the counter-electromotive force equals E,. This is the condition with windin S directly the winding M equals the field of winding P, the motor runs synchronously. On this principle may be provided a starting and controlling system whereby for example the stator is subjected to a nearly constant voltage while the rotor has impressed upon it a voltage of lesser ratio to the voltage of the stator than the ratio of windings, the difference of the quotients of the impressed voltage and the number of turns of stator and rotor respectively being in accordance with the speed required. The speed is also dependent upon the strength and phase of the magnetic field produced by the winding M and consequently, by variation-of these magnitudes, a regulation can also be produced. With the same object in view the rotor potential can be maintained constant and the stator potential varied. If the'rotor is turning and is then subjected to a potential corresponding to a: higher number of revolutions then it advances to the higher speed but if on-the other hand it is subjected to a potential which corresponds to a lower number of revolutions, then it acts as a brake and as a dynamo gives ener y back to its circuit until its speed is su%- ciently reduced. When a means of driving is provided such machines may be caused to act permanently as dynamos and then be connected in parallel as easily as ordinarily continuous current dynamos.

In the arrangement shown in Fig. 1 the winding M is placed'on the rotor and is provided with a commutator distinct from the commutator to which the winding S is connected. The winding P is subjected to the full potential E and the winding S to suitably reduced potential E supplied through asystem of brushes B and B and the segmental commutator. An electromotive force- 0 1s supplied to the'windin M through a second system of brushes. 8 and B arranged in the linekwire y y.

In Fig. 2 the winding M is combined with the winding S, only a sin 1e commutator being employed. Instead ofconnectin the rotor with the secondary winding 05 the transformer divided into potential graduations, as shown in Fig. 2, it may be connected with or to an impedance which .utilizes resistance, inductance, or capacity; the torque being determined by the adjusting of the impedance. Such an arrangement is shown in Fig. 3, in which the windin S is closed through a variable resistance. f the impedance is made very small,-- that 'is, should the terminals be short-circuited-then E would be 'zero and winding P subjected to E as before, and current flowing through winding M again provides the excitation either by the stator or the rotor. Fig. 4 shows an arrangement-in which winding S is directly short-circuited.

In the arrangements described heretofore it is evident that the field produced on S. Therefore, it will be seen that-the two fields tend to produce a rotary field which is more or less uniform, according as the two component fields vary in relative strength and the phase of the currents in windings P and S varies relatively to the voltage impressed on winding P. It is not necessary, however, that the twocomponents of this rotary field should be produced by currents coming from external sources of voltages of different phases. The magneticfield M may be excited by current coming from the brushes, and in that case a field winding system of few turns would be used in order to permit the use of a low voltage at the commutator, instead of a system of many turns, such as would besuitable when field M is excited from the external source of comparatively high voltage. Fig. 5 shows such an arrangement. In this figure wind ing M is connected in series with winding '2 S. With this arrangement the field M must obviously be always in phase with the rotor current.

Not only the arrangement of apparatus illustrated in Fig. 1 but also the other apparatus hereinafter described, can be used as generators because, upon excitation through a determined magnetic field, an electromotive force must in all cases arise 40 at the rotating armature and this electrometive force, quite independently of the number of revolutions of. the rotor, is equal in phlase and periodicity with the magnetic e d. All the figures relates to bi-polar arrangement and therefore-only represent examples of construction. For an apparatus having' windings, such as are used for continuous currents and with segmental commutators can be used.

Wghat we claim as new and desire to secure by Letters Patent of the United States, is,

1. An alternating current motor of the commutator type, having brushes cooperating to form for each pair of primary poles,

first, a path along the line of the primary field for the currents induced in-thearmature, and second, means for feeding a magnetizing current from outside for generating the torque-producing field of the motor.

2. In an alternating-current motor of the commutator type, brushes and connections therefor coeperating to form for each pair of primary poles, first, a path along the line of the primary field for thecurrents induced in the armature, and second, means for generating at all speeds a torqtie-producing field by feeding an appropriate magnetizing current from outside to the armature and separate means for impressing a counter-electromotive force on the armature.

'3. In an alternating-current motor of th commutatortype, brushes and connections therefor cooperating to form for each pair of primary poles, first, a path along the line 86 of the primary field for the currents induced injthe armature, and second, means for generating at all speeds a torque-producing field by-feeding an appropriate magnetizing current from outside to the armature and sepa- 90 rate means for impressing a variable counter-electromotive force on the armature. I

4. In an alternating-current machine of the commutator type, brushes and connections therefor cotiperating to form for each .95 pair of primary poles, first along the line of the primary field (z'. e. the working-axis),

a path approximating the same axis for-the working currents in the armature, and second, means for feeding from out-side to the armature a magnetizing current, ,theconnectionsfor feeding said magnetizing current being arranged to supply at all speedscurrent substantially in phase with said working-currents and' separate means for impressing a variable counter-electromotive force on the armature.-

5. In an alternating-current machine of the commutator type, brushes and connections therefor coiiperating to form for each pair of primary poles, first along the line of the primary field e. the working-current axis), a path'approximating the same axis for the working-currents in the armature, and secondyseparate brushes for feeding from outside a magnetizing current to the armature, the connections for feeding said magnetizing current being arran ed, to supply at all speeds current substantlally in phase with said working-currents and separate means.for impressing a counter-electromotive force on the armature.

6. In an alternating-current machine of the commutator type, brushes and connections therefor cotiperating to form for each pair of primary poles, first, a path along the line of the primary field for the currents inv duced in the armature, and second, means for generating at all speeds a torque-producing field by feeding an appropriate magnetizing current from outside to the armature.

7. In an alternating-current machine of the commutator type, brushes and connections therefor cooperating to form for each pair of primary poles, first alongthe' line of the primary field e. the Working-current axis), a path approximating the same axis for the Working currents in the armature, and second, meansfor feeding from outside to the armature at all speeds a mag.- netizing current, substantially in phaseWith said Working-currents 8; In an alternatingcurrent machine of the commutator type, brushes and connections therefor cooperating to form for each pair of primary poles, first along the line of the primary field e. the Working-current axis), a path approximating the same axis for the Workingcurrents in the armature, and second, separate brushes for feeding from outside to the armature at all speeds a Copies at this patent-may be obtained for our hands this 30th dayof June, 1906.

GABRIEL WINTER FRIEDRICH EICHBERG.

Witnesses'as to Gabriel Winter;

ALVESTO S; HOGUE,

. AUGUST FUGGER.

Witnesses as to Friedrich Eichberg:

HENRY HAsPnR, YVOLDEM'AR HAUPT.

five cents each, by addressing the Commissioner of Patents, Washington. D. C. y a 

